<template>
	<view>
		<view class="scroll-view-container">
      <!-- 左侧滚动容器 -->
		  <scroll-view class="left-scroll-view" scroll-y="true" :style="{height:wh + 'px'}">
		    <block v-for="(item, i) in cateList" :key="i">
          <view :class="['left-scroll-view-item', i === active ? 'active' : '']" @click="activeChanged(i)">{{item.cat_name}}</view>
        </block>
		  </scroll-view>
      <!-- 右侧滚动容器 -->
      <scroll-view scroll-y="true" :style="{height:wh + 'px'}" :scroll-top="scrollTop">
       <view class="cate-lv2" v-for="(item2, i2) in cateLevel2" :key="i2">
         <!-- 二级分类的标题 -->
         <view class="cate-lv2-title">
           / {{item2.cat_name}} /
         </view>
         <!-- 二级分类下面的三级分类 -->
         <view class="cate-lv3-list">
           <view class="cate-lv3-item" v-for="(item3, i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
             <!-- 三级分类的图片 -->
             <image :src="item3.cat_icon"></image>
             <!-- 三级分类的文字 -->
             <text>{{item3.cat_name}}</text>
           </view>
         </view>
       </view>
      </scroll-view>
		</view>
	</view>
</template>

<script>
	export default {
		data() {
			return {
				// 可用区域的高度
        wh:0,
        // 分类列表数据
        cateList:[],
        // 激活项
        active:0,
        // 二级分类数据
        cateLevel2:[],
        // 动态绑定举例顶部的位置
        scrollTop:0
			};
		},
    onLoad(){
      const sysInfo = uni.getSystemInfoSync()
      // console.log(sysInfo)
      this.wh = sysInfo.windowHeight
      // 获取分类列表数据
      this.getCateList()
    },
    methods:{
      // 获取分类列表数据
      async getCateList(){
        const {data:res} = await uni.$http.get('/api/public/v1/categories')
        if(res.meta.status !== 200) return uni.$showMsg()
        this.cateList = res.message
        // 为二级分类赋值
        this.cateLevel2 = res.message[0].children
      },
      activeChanged(i){
        this.active = i
        // 重新为二级分类赋值
        this.cateLevel2 = this.cateList[i].children
        // 让右侧滚动条置顶
        this.scrollTop = this.scrollTop === 0 ? 1 : 0
      },
      // 跳转到商品页面
      gotoGoodsList(item){
        uni.navigateTo({
          url:'/subpkg/goods_list/goods_list?cid=' + item.cat_id
        })
      }
    }
	}
</script>

<style lang="scss">
 .scroll-view-container {
    display:flex;
    .left-scroll-view{
      width: 120px;
      .left-scroll-view-item {
        background-color: #F7F7F7;
        line-height: 60px;
        text-align: center;
        font-size: 12px;
        &.active {
          background-color: #FFFFFF;
          position: relative;
          &::before{
            content: ' ';
            display: block;
            width: 3px;
            height: 30px;
            background-color: #C00000;
            position: absolute;
            top: 50%;
            left: 0;
            transform: translateY(-50%);
          }
        }
      }
    }
}
.cate-lv2-title {
  font-weight: bold;
  font-size: 12px;
  padding: 15px 0;
  text-align: center;
}
.cate-lv3-list {
  display: flex;
  flex-wrap: wrap;
  .cate-lv3-item {
    width: 33.33%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    margin-bottom: 10px;
    image {
      width: 60px;
      height: 60px;
    }
    text {
      font-size: 12px;
    }
  }
}
</style>
